Docker is a program used to package applications and their dependencies into bundles that can run on any computer. A running instance of the bundle is a container. Docker containers help developers build software by isolating applications, sandboxing projects, and guaranteeing running software. To have a docker container, one needs to write a Dockerfile, build it into an image, and run the image. When I was learning the process, my instructor explained the process and terms by using only an analogy. He compared them to the process of how source files became executables, and then running processes.  Because analogies only help understand concepts (not define them), the goal of this post is to define Dockerfiles, images, and containers as well as their relationships. To achieve the goal, I will be using information from the article, “Differences Between Docker Images and Containers,” written by Eugen Baeldong, an author who has written about software development extensively. His article differentiates Docker images from containers.

The Dockerfile is a text file that contains instructions on how to find, install, and configure an application and its dependencies. In the same way an embryo is a baby at the first stage of development, a Dockerfile is a container at the first stage of development. Some commands that can be used to create instructions are RUN and COPY. RUN is used to install a package or application and COPY is used to copy files and directories from one location to another. With the commands, instructions are created. The set of instructions tell a computer how to find and install the applications and its dependencies.

When a computer executes the instructions in a Dockerfile, an image is built. According to Baeldong, an image is a template for creating the environment one wants. In other words, it is a snapshot of a system one wants. Returning to the baby analogy, an image is a container at the second stage of development in the same way a fetus is a baby at the second stage of development.  I imagine an image as one’s desktop environment. The icons in the environment represent the application and its dependencies in a dormant state. The application is not running yet in the same way desktop applications do not run until one double-clicks their icons.

When a computer runs an image, a container is created. A container is an environment where an application and its dependencies are running. The application in the container is independent from the applications on the computer. In other words, the contents inside a container and one’s computer are unaffected by one another. I imagine it as a computer inside a computer; however, the second computer will not have a graphical interface because it is not necessary for an application to run.

https://www.baeldung.com/ops/docker-images-vs-containers

From the blog CS@WORCESTER – Andy Truong's Blog by atruong1 and used with permission of the author. All other rights reserved by the author.

Since we’ve been using JavaScript for the past several weeks in class and in homework, I thought it would be beneficial to help run through some elements of JavaScript I found weird or difficult at first. I’ve noticed some people have a harder time understanding JavaScript’s syntax or how its variables work, so I wanted to make this as a sort of reference.

Types

JavaScript contains primitive and non-primitive types. A variable can be declared with “var”, “let”, or “const”, more on const later. The main primitive types are¹:

• Boolean: true, false
• Null: null
• Undefined
• Number: 72, -174.21
• String: “Hello, ”, ‘world’

For an object type, objects are very loose and can for the most part be defined with relative ease. 

Let’s take a simple object, named “car”.

This object has three properties, wheels, year, and color. When declaring or assigning properties, the syntax shifts from the typical use of “var num =”, to “num: ”. These properties in an object are pairs: “wheels” and “4” are a pair, specifically a key-value pair as well as an object. This means that there is more than one way to access an object’s properties. 

The second one looks suspiciously similar to a map, specifically one in C++. Objects may be iterated through using a for-loop directly.

Functions

Functions may be defined in a few ways. If inside of an object, the function would be defined as:

Else, it may be defined as the following:

The bottom function declaration is known as arrow notation. A function with arrow notation is not bound to an inherited constructor or the keyword “this”, and its usage with scopes may be troublesome. Its parentheses may be dropped if there does not exist any parameters, such as “getProps => {}”².

JSDoc

JSDoc is a markup language used to comment JavaScript code, and is similar to JSDoc in many ways. JSDoc may be created by typing “/**”, then pressing enter upon this pop up:

JSDoc is, in my opinion, very useful in declaring classes, functions, objects, types, or declaring types. This is especially important with JavaScript, since types are handled dynamically.

JSDocs can use the following my pressing “@” inside of the comment, revealing a large list of descriptors, with users being able to make any and anytime³:

Upon creating a simple JSDoc annotation:

Hovering over the object “car” will read:

For our function getValue:

This is rendered as: 

Hopefully, this post can be helpful. JavaScript was odd for me when I first started, with these topics being some of the things that took me a while to get used to. The sources contain a wealth of information that I have and will continue to refer to and learn from, and hopefully they can help you too.

Links:

1. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures (Types)
2. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions (Arrow Functions)
3. https://www.typescriptlang.org/docs/handbook/jsdoc-supported-types.html (JSDoc)

From the blog CS@Worcester – Chris's CS Blog by Chris and used with permission of the author. All other rights reserved by the author.

https://www.toptal.com/css/why-you-need-a-css-developer

Keeping in line with my front-end blog posts, I wanted to read another blog post on front-end stuff so I decided to pick this blog post from toptal.com on CSS developers. I also decided to choose this blog post because I think CSS is the first programming language I was aware of, I only knew that it was part of web design but I was always confused looking at it’s syntax. In this blog post from Silvestar Bistrović, he runs over what CSS developers do and why we need one.

He introduces the reader with CSS developers and what they are. They’re web professionals whose primary responsibility is to deliver a polished and styled product to the visitor’s browser. Practically every website uses CSS, but CSS is often not considered an “equal” in the modern web development stack. This has led to CSS being taken for granted, sometimes even overlooked. He then goes on to explain why CSS developers are a necessary good and to have a dedicated CSS developer instead of someone who isn’t.

The blog post is sectioned into 3 sections: What Do CSS Developers Do, Why Do You Need a CSS Developer, and Wrapping Up with every section having subsections explaining further on the section. What Do CSS Developers Do covers what they do, CSS tools, techniques, and principles, CSS, the fact Javascript is everywhere, and that writing tidy HTML always matters. Why Do You Need a CSS Developer covers CSS coding standards, CSS design implementation, organizing your CSS code, CSS code in production, and what CSS developers can do for you. Wrapping Up is self explanatory, it’s a conclusion.

As mentioned earlier, CSS was the first programming language I stumbled upon. I stumbled upon it as a kid playing online games and trying to customize my profiles for sites. I didn’t know what it was at the time and just took CSS code from others and used that to format my profile for those online games. It wasn’t until now that I would stumble upon it again in class during In-class activity 15-16 and realize how important it actually is. CSS is one of the forefronts of frontend design and that was something I didn’t know until now because I haven’t dipped my toes in web dev stuff yet. At first I thought front-end web developers were supposed to be jack of all trades for front-end development but after reading this I think having someone who specializes in CSS is essential to your team and as the author says, “do you want to leave your product in the hands of a specialized professional that could polish it to perfection, or would you settle for good enough?”

From the blog CS@Worcester – Brendan Lai by Brendan Lai and used with permission of the author. All other rights reserved by the author.

The speaker in this podcast is Alen Pokos, a deputy chief technology officer at Trikodor, a software development company specializing in UX (user experience) and natural language processing for computers, think Siri/Cortana. He spends this hour discussing API design and ideas on how to approach designing web APIs as well as giving personal accounts of his time in the industry and the solutions for common problems he’s encountered.

He begins the presentation defining API as something that enables applications to communicate with one another, it should reflect the goals of the business it is designed to serve, as well as giving a brief description of REST. Pokos goes on to explain common scenarios where Web APIs are usually built; being for other web servers or client consumers such as a web browser or mobile application.

The topic covered in the video that I found most compelling, and really where a lot of the value I gleaned was, was API design. This is primarily what his company presents itself as being experts in. He very poignantly states that “When people disagree on design, it is often they do not agree on the goals.” I’ve run into this situation when designing other things, be it in woodworking, Information Security, Hardware deployment, you name it. It’s something that should really be agreed upon before a project begins which is why software process management strategies all have some form of a task list where goals of development are clearly stated and agreed upon prior to actual development. It is important that before you decide on how a project accomplishes its task, you know what the task is.

I chose this episode because we are currently studying API, frontend, and backend development for the Libre Food Pantry. Understanding the context of what we’re doing and how it may relate to the industry is important for maintaining a firm perspective of how I could potentially translate the skills I’m cultivating into a professional workplace.

From the blog CS@Worcester – Jeremy Studley's CS Blog by jstudley95 and used with permission of the author. All other rights reserved by the author.

https://blog.bitsrc.io/9-best-practices-for-optimizing-frontend-loading-time-763211621061

So last week I wrote a blog post on good practices for REST API design so naturally I had to follow it up with a blog post on good practices to follow on optimizing frontend performance since we’re working with frontend stuff this week.

This week’s blog post is about a blog post from bitsrc.io from Nethmi Wijesinghe titled “9 Best Practices for Optimizing Frontend Performance.” In this blog post, she writes about 9 best practices that will be useful to the reader to optimize frontend data loading. The 9 best practices she lists are: minify resources, reduce the number of server calls, remove unnecessary custom fonts, compress files, optimize images, apply lazy loading, caching, enable prefetching, and use a content delivery network.

To summarize the 9 practices:

1. Minify Resources: remove unnecessary, redundant data from your HTML, CSS, and JavaScript that are not required to load, such as code comments and formatting, etc.
2. Reduce the Number of Server Calls: More calls to server, more time to load. 3 ways to reduce the number of server calls include: using CSS sprites, reducing third party plugins, and preventing broken links.
3. Remove Unnecessary Custom Fonts: Self explanatory, but also you can take these 3 actions when using fonts on your website like, converting fonts to most efficient format, subset fonts to remove unused characters, and preloading fonts explicitly required.
4. Compress Files: Compress files to save loading time since larger files = longer loading time.
5. Optimize the Images: Images improve user engagement but make sure they are optimized to save loading time.
6. Apply Lazy Loading: Lazy loading allows web page to load required content first and then remaining content if needed
7. Caching: Allow caching so browsers can store the files from your website in their local cache and avoid loading same assets when revisiting
8. Enable Prefetching: Prefetching loads the resource in anticipation of their need to reduce the waiting time of the resource.
9. Use a Content Delivery Network: Using a CDN (group of servers distributed across several geographical locations that store a cached version of the content to deliver fast to the end-user) allows you to optimize loading time as well.

I picked out this blog post because we were using frontend in class during Activity 15-16 and I wanted to follow up with practices to optimize your frontend. This was one I found that was interesting but also introduced new terminology to me. Things like lazy loading, prefetching, and CDNs I didn’t know about until this reading this post. Also, I haven’t had any web dev experience prior to this class and doing the in class activities made me more interested because it was something new to me I had never touched. I knew web dev things existed I just never knew how complex it can actually get and it’s actually made me more interested in possibly pursuing a web dev position instead.

From the blog CS@Worcester – Brendan Lai by Brendan Lai and used with permission of the author. All other rights reserved by the author.

Hello everyone, hope you are all doing well. As this is the final week, I would like to wish you all Goodluck with your finals. In this week’s blog, I would like to talk about Refactoring as it is one of the important parts of programming. Refactoring is a process of restructuring code while making sure it does not change the original functionality of the code. The main goal of refactoring is to improve internal code by making small changes without altering the code’s external behavior.

Computer programmers and software developers refactor codes to improve the design, structure, and implementation of software. Refactoring improves code readability and reduces complexities. It also helps software developers find bugs or vulnerabilities hidden in their software. Refactoring improves codes by making them more efficient by addressing dependencies and complexities, becomes more maintainable and reusable by increasing efficiency, makes the code cleaner which then makes the whole code easier to read and understand, these are a few purposes of refactoring.

Refactoring can be performed after a product has been released, this should be done before adding updates and new features to the existing code or it should be done as a part of day-to-day programming. There are several benefits of refactoring like it makes the code easier to read, encourages a more in-depth understanding of code, improves maintainability. It also comes with various challenges like this process will take extra time if the development team is in the rush to finish the product and refactoring is not planned for, without clear objectives refactoring can lead to delays and extra work, Refactoring cannot address software flaws by itself, as it is made to clean code and make it less complex. There is various technique to refactor the code some of the examples include moving features between objects, Extracting, refactoring by abstraction, and composing. The best practices to follow for refactoring include Planning for refactoring when a project starts, Developers should refactor first before adding updates, refactor in small steps, Test often while refactoring, fix software defects separately, Understand the code before refactoring, focus on code deduplication, use of Automation tools make refactoring easier and faster.

I choose this article because it has a clear definition of refactoring and purpose of refactoring, benefits of it, explains different techniques to perform code refactoring, and gives best practices to follow for refactoring and since it is very helpful for software engineers, in the future these practices will help me do my job easier and help me do my job in an effective way.

Article: https://searchapparchitecture.techtarget.com/definition/refactoring

From the blog CS@Worcester – Mausam Mishra's Blog by mousammishra21 and used with permission of the author. All other rights reserved by the author.

https://derisking-guide.18f.gov/state-field-guide/basic-principles/

Something I struggle with quite a bit is directing my personal software projects. Staying committed, composing large pieces of code with each other correctly, and even figuring out what I want to do in the first place are all things that I just sort of play by ear, with limited success. In an attempt to gain some insight, I found this article published by a technology and design consultancy for the US government, directed at non-technical project managers. The gist of it is that these managers must understand six concepts: user-centered design, Agile software development, DevOps, building with loosely coupled parts, modular contracting, and product ownership. I won’t go into all of these, since some are still more technical than others, but I want to highlight a few.

One of my favorite points in the article is something that I’ve believed for a long time, which is that all development should be centered on the needs of the end user, rather than stakeholders. Project risk is reduced by ensuring the software is solving actual problems for actual people, and the problems are identified via research tactics like interviews and testing for usability. It would be kind of silly to interview myself, but I think this is a good mindset to have. It kind of sounds meaningless when stated so directly, but if you want a product you have to focus on creating the product, rather than daydreaming about every possible feature it could have.

Another point I liked was the discussion of Agile software development. Without getting too into the weeds on details, the basic problem it seeks to solve is that detailed, long term plans for major custom software projects generally become incorrect as the project proceeds and new technical considerations are discovered. To combat this, agile developers plan in broad strokes, filling in details only as necessary. In a way, it kind of reminds me of an analogy I heard once to describe Turing machines – an artist at their desk, first drawing a broad outline and then focusing on specific sections and filling in details (it may or may not be obvious how this is related to Turing machines but that’s not relevant). The primary metric is how fast documented and tested functionality is delivered.

I found two other somewhat related points useful as well, both of which deal with modularity. The first is the idea of “building with loosely coupled parts”, which essentially boils down to the idea that if one agile team is in over their head, they should split the work into two or more distinct products each with its own dedicated team. Modular contracting is just applying this concept before even beginning a project. Together, I think this a helpful way of possibly connecting all the small fleeting app ideas I have – rather than one unfocused monolith, I could work on a small ecosystem with a shared API that I add and remove things from as needed.

From the blog CS@Worcester – Tom's Blog by Thomas Clifford and used with permission of the author. All other rights reserved by the author.